Brown bear 410 on a gravel bar near Brooks River (US National Parks Service)

Accepted scientific name:  Ursus arctos gyas (Clinton Hart Merriam, 1902); however many authorities recognise only two subspecies of brown bear in North America: the grizzly bear (U.a. horribilis) and the Kodiak bear (U.a. middendorffi).  This places the bears of the Alaska Peninsular in the subspecies U.a. horribilis.

In 1918 Clinton Hart Merriam divided the North American brown bears into 86 subspecies based upon small physical differences, mainly relating to skull measurements.  Over time this list has been reduced but some experts believe that there is still sufficient evidence to warrant classifying five North American subspecies in addition to the widely accepted grizzly and Kodiak bear subspecies.  In this website we include those five subspecies; the Peninsular (U.a. gyas) brown bear  being one of them.  However, much of the following information, other than range, is similar or identical to that given on the pages for the Alaskan (U.a.alascensis), Dall (U.a. dalli), Sitka (U.a. sitkensis) and Stickeen (U.a. stikeenensis) brown bears.

Description:  A large bear, most commonly dark brown in colour but can range from blonde through to black.  The often grizzled appearance is caused by the light coloured tips of the long guard hairs over the shoulders and back.  The bears have a distinctive hump on the shoulders and a slightly dished profile to the face.  The front claws are noticeably long.  There is considerable variation in size depending upon the food available.  Adult males typically weigh 135 to 390 kg, females 95 to 205 kg.  Adults are usually between 90 and 110 cm at the shoulder.  These bears are usually larger than those of the interior (due to the larger amounts of protein in their diet).

Range:  Alaska Peninsula and Unimak Island in the Aleutian Islands; includes the famous populations at McNeil River and Katmai.

Map of Alaska Peninsula & Unimak Island showing US National Wildlife Refuges (U.S. Fish & Wildlife Service)

Habitat:  The southern side of the Alaska Peninsula is rugged and mountainous, the northern side is generally flat and marshy. The large lakes and connecting rivers of the peninsula are important to the bears as the spawning sites of salmon.

Alaska Peninsula: Brown bear playing with a stick, near Brooks Camp, Katmei (US National Parks Service)

Status:  Brown bears are listed as “of least concern” by the IUCN and listed in CITES Appendix II.  There are around 30,000 brown bears in total in Alaska (excluding the subspecies U.a.middendorffi).  Stable and large population, hunting seems to be within sustainable limits.

Life span:  Around 20 to 30 years in the wild.

Food:  The bears are omnivorous and eat plants, grasses, sedges, roots, tubers, seeds, berries, tidal vegetation,sockeye and chum salmon, small mammals and carrion.  They will also predate upon moose, particularly newborn animals.Sockeye salmon, chum salmon, tidal vegetation.

Behaviour:. The bears reach sexual maturity between the ages of four and seven years.  Mating occurs between May and July.  The bears go into winter dens usually in October or November and emerge in April, or May.  Cubs are born in the den in January and February, litters usually being of two or three cubs but can be of one or four.  They will remain with the mother about two and a half years during which time she will not become pregnant again.  Except for mating and for mothers with cubs, grizzly bears are solitary although they will congregate in groups where there are plentiful sources of food, such as spawning salmon, whale carcasses and sedge fields.

Threats:  As with other Alaskan bears there is the risk of habitat loss, habitat fragmentation, and the resultant conflicts with humans.  Poaching including for body parts to be used in medicine seems to be an increasing threat for all bears.  Hunting is generally well regulated and based upon reliable population estimates.  It seems likely that these bears are or will soon be affected by climate change either directly or indirectly as habitat and food sources change or disappear.Hunting, conflicts with humans.


Alaska Pensinsula National Wildlife Refuge

Page updated 06 August 2017









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